Salts of quaternary cations and anions, in particular quaternary salt phenolate solutions, prepared from deprotonated hydroxy aromatics may be utilized as bases, catalysts or a reaction component in a range of organic reactions. Because such salts are not available commercially and their educts are relatively costly, there exists a need for methods of, on the one hand, synthesising these salts and, on the other, of recovering them from reaction mixtures.
DE A 19858967 describes a process for the preparation of liquid formulations of tetrabutylammonium phenolate. Here, phenolic solutions of tetrabutylammonium bromide and sodium phenolate are combined, excess phenol is distilled off, and sodium bromide is filtered off.
The disadvantage of this process is, on the one hand, the necessity of preparing sodium phenolate and distilling off phenol, with concomitant energy consumption, and, on the other hand, the optional difficulty of separating the sodium bromide which arises, which may be a very finely crystalline precipitate. It is therefore desirable to devise a simpler process having a lower capital cost requirement. A further object relates to the recovery of quaternary cation phenolate salts from reaction mixtures. The process should therefore also offer the possibility of working up reaction mixtures such that the quaternary cation phenolate solutions are able to be recycled again.